python: Move more code into m5.util allow SCons to use that code.

Get rid of misc.py and just stick misc things in __init__.py
Move utility functions out of SCons files and into m5.util
Move utility type stuff from m5/__init__.py to m5/util/__init__.py
Remove buildEnv from m5 and allow access only from m5.defines
Rename AddToPath to addToPath while we're moving it to m5.util
Rename read_command to readCommand while we're moving it
Rename compare_versions to compareVersions while we're moving it.

--HG--
rename : src/python/m5/convert.py => src/python/m5/util/convert.py
rename : src/python/m5/smartdict.py => src/python/m5/util/smartdict.py

configs/example/memtest.py

@@ -26,10 +26,11 @@
 #
 # Authors: Ron Dreslinski
 
+import optparse
+import sys
+
 import m5
 from m5.objects import *
-import os, optparse, sys
-m5.AddToPath('../common')
 
 parser = optparse.OptionParser()